I just want to record these calculations in their own thread to refer back to in other threads.

When alkalinity is too high in new salt water or in a display tank, acid can be used to lower the alkalinity. You can easily use muriatic acid (hydrochloric acid), or sodium bifulfate (e.g., Seachem Acid Buffer is this chemical, I think) or sulfuric acid (but that one is harder to get for hobbyists).

Note that these methods reduce pH a lot (and to the same extent), until you aerate adequately, so go very slow in a display and aerate a lot to drive off the excess CO2 that is generated.

Dropping alk by 1.4 dKH when starting at 6.3 dKH will drop pH below 7 (I got 6.9, experimentally). The effect is roughly linear with alkalinity, so starting at 12.6 dKH, a drop of 2.8 dKH will drop the pH to around 7 or a bit lower (depends on the starting pH, of course).

Sodium bisulfate is NaHSO4.

In seawater, it releases H+:

NaHSO4 ---> Na+ + H+ + SO4--

The H+ is what reduces the alkalinity, and the Na+ and SO4-- are not any concern:

I just want to record these calculations in their own thread to refer back to in other threads.

When alkalinity is too high in new salt water or in a display tank, acid can be used to lower the alkalinity. You can easily use muriatic acid (hydrochloric acid), or sodium bifulfate (e.g., Seachem Acid Buffer is this chemical, I think) or sulfuric acid (but that one is harder to get for hobbyists).

Note that these methods reduce pH a lot (and to the same extent), until you aerate adequately, so go very slow in a display and aerate a lot to drive off the excess CO2 that is generated.

Dropping alk by 1.4 dKH when starting at 6.3 dKH will drop pH below 7 (I got 6.9, experimentally). The effect is roughly linear with alkalinity, so starting at 12.6 dKH, a drop of 2.8 dKH will drop the pH to around 7 or a bit lower (depends on the starting pH, of course).

Sodium bisulfate is NaHSO4.

In seawater, it releases H+:

NaHSO4 ---> Na+ + H+ + SO4--

The H+ is what reduces the alkalinity, and the Na+ and SO4-- are not any concern:

@Randy Holmes-Farley I'm curious would you say that Sodium Bisulfate is less hazardous to work with than Muriatic acid for this application (ie fumes)? It seems like sodium bisulfate would be easier to store in an apartment so it may be my choice

@Randy Holmes-Farley I'm curious would you say that Sodium Bisulfate is less hazardous to work with than Muriatic acid for this application (ie fumes)? It seems like sodium bisulfate would be easier to store in an apartment so it may be my choice

Been toying around with the idea of using muratic acid to being down alk of IO. I have some but it's the hardware store variety.
Given a choice I would definitely prefer a lab or food grade option. And the added safety is a plus.

Would any of you geniuses be kind enough to convert this into grams required to drop 1 gallon by 1 dKH? TIA

So the same dosing applies to the seachem product? or only to the ones you are linking to?

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From the sound of Randy's post, he is unsure if Seachem's product is sodium bisulfate. It's rather uncommon for manufacturers to be up-front about what kinds of chemicals they put in their supplements. If you are using the Seachem product, it's probably best to follow the exact directions on the product.

From the sound of Randy's post, he is unsure if Seachem's product is sodium bisulfate. It's rather uncommon for manufacturers to be up-front about what kinds of chemicals they put in their supplements. If you are using the Seachem product, it's probably best to follow the exact directions on the product.

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They only provide dosing information to drop pH and in FW I believe.
If anyone has a link to a thread where dosing for the seachem acid buffer is shown for this application please share.

What about the sodium bisulfate that is sold for pools? Is that safe to use in aquariums?

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What @VbReefer said. It might be safe. But, it might not. Sodium bisulfate likely does not need to have low impurities to work in pools. There are, however, lots of elements that are problematic for reef tanks at very low levels. Impurities that might not be a problem for pools could be a big problem for reef aquaria. Food-grade products, on the other hand, must be sufficiently pure for human consumption. In general, stuff that is safe for humans appears to be safe to put in reef tanks.